Connecting two sub1/sub2 with XLR through submatch cable is NOT working

The instruction manual (and the Bose YouTube video) say that two subs can be connected via submatch cable, using XLR cable from source. This configuration does NOT work with me.
Trying to connect two subs to my DJ rack. 
—>Mixer to 1st Sub2 via XLR. 1st Sub2 to 2nd Sub2 via submatch cable. Power but no sound coming out of 2nd Sub2. 
Does the submatch cable only transmit sound signal when signal input in 1st sub is from submatch cable? This is not what Bose says in the instructions. 
please help?

Hi DJ Heisenberg!

Please see my response to this query on this thread.

  thanks! Really appreciate you taking the time to reply! 

I asked another question to your reply, on the other thread. Thank you in advance! 🙂